As a former country girl and neophyte container gardener with a 4' x 3' east-facing fire escape landing along with 3 huge south-facing windows, the idea of having to purchase and then continually fertilize...

Of particular note, this from the above-linked school composting piece:

"Much of New York’s compost stream is a result of nutrition rules that require every child to be served healthy food, and health rules that ban re-serving unwrapped food once it has been placed on a lunch tray, for fear of contamination and to make sure food is served at proper temperatures. For those reasons, an uneaten apple or banana or even an unopened milk carton cannot be given to another child."

And this:

"At P.S. 30, students done with their lunch have a choice of three plastic bins: one for landfill garbage like plastic bags, foam cups and wrappers; one for recyclables, like metal, glass, plastic and milk cartons; and one for food scraps. Nearby is a red bucket where unconsumed milk is poured; it is later sent down a drain."

Milk. If they have kids separating stuff and pouring milk down a drain, here's a source for the milk part of the Bokashi-making equation.

How hard would it be to get a Starbucks corporation behind collecting its grounds to use as the substrate? Is a substrate / drying / storing process even necessary in a hybrid system? A light spray of diluted EM with each layer added to the hybrid compost pile...

Now all we need are free sources of molasses and rice wash water to complete the ingredient list.